CD-R and CD-RW disks have absolute-time information called ATIP (Absolute Time In Pregroove) time information in a guide groove known as a pregroove. In addition to the ATIP time information itself, area discrimination information for distinguishing a lead-in area, a data area and other areas from each other is also recorded.
In the conventional seek operation, the present position is compared with a seek-target position for confirmation of the seek-target position on the basis of the ATIP time information.
It is to be noted that Page 3 of Japanese Patent Laid-open No. 2001-351311 discloses that data is read out and written from and onto a writable optical disk while this ATIP (Absolute Time In Pregroove) time information is read out from the pregroove.
In addition, the abstract of Japanese Patent Laid-open No. 11-306701 discloses a configuration for detecting rotational phenomenon of a stepping motor serving as a slide motor of an optical pickup of the optical storage device. (Hereinafter, it is solely called “irregularity phenomenon”.)
Recently, CD-R and CD-RW disks are made available in the market as disks each having a total data area with a size equivalent to a recording time period of at least 80 minutes. In these optical disks, however, the format of the ATIP time information does not include margin bits for particularly indicating the total data area with a size equivalent to a recording time period of at least 80 minutes. Thus, the ATIP time information of the lead-in area cannot be distinguished from that of the total data area with a size equivalent to a recording time period of at least 80 minutes.
For the above reason, with the conventional way of carrying out a seek operation, a seek operation based on ATIP time information cannot be implemented. Therefore, in the conventional way of carrying out a seek operation, inevitably, only a write operation can be started from a data-area location inside a region with a size equivalent to a recording time period smaller than 80 minutes and continued to a data-area location outside the region with a size equivalent to a recording time period smaller than 80 minutes in the operation of an over-burn function.
It is thus an object of the present invention to provide a seek method of seeking a position in a first, a second, and a third area included in an optical disk, in which the first area has time information, the second area has time information undistinguishable from the time information of the first area, and the third area has unique time information, as well as provide an optical storage device.
It is another object of the present invention to provide an optical disk seek method of avoiding a malfunction occurring in a seek operation due to an irregularity phenomenon as well as an optical storage device.